Air conditioning systems, such as those used in passenger cars, vans, and trucks, include a closed system for refrigerant flow. The refrigerant is circulated in a set of closed lines and components generally referred to as comprising the refrigeration cycle.
In the system, an evaporator cools, dries, and cleans the air that enters the passenger compartment. In operation, refrigerant enters the evaporator as a low pressure mixture of liquid and vapor. The liquid vaporizes at the low pressure, absorbing large quantities of heat from the passing air. As the heat is transferred through the walls of the evaporator from the air passing over it, moisture in the air condenses on the surface and is drained off, carrying dust and pollen with it.
In prior art systems, a fluid line connects the evaporator to an accumulator. The accumulator collects refrigerant liquid, separating the liquid from the vaporized refrigerant. The accumulator is a collection point for liquid, a separator of liquid and gas, and a filtration area. The accumulator may also function as a sound attenuating device.
The fluid line between the evaporator and accumulator presents a problem in that there is thermal loss from the tube, as well as from the other exposed surfaces of the assembly. For example, present automotive air conditioning systems sometimes locate the accumulator at a significant distance from the evaporator. The combination of the surface area of the accumulator, extended fluid line, and evaporator, and additional connector pipes in combination result in thermal loss and a decrease in the efficiency of the system. The extended fluid line also causes a pressure drop between the evaporator and accumulator housings.
Some prior art automotive air conditioning systems include an evaporator housed in an evaporator blower assembly. The assembly includes a plastic casing surrounding the evaporator which guides air from a blower or fan through the evaporator core. In these systems, the accumulator is outside of the evaporator blower assembly and thereby outside of the air stream flowing through the plastic casing.
In combination with the above considerations, present day automotive designs minimize the engine compartment space. Therefore, it is desirable to minimize the space requirement for the components of the air conditioning system.
Another consideration in the manufacture of air conditioning systems is the labor and manufacturing costs. Presently, air conditioning systems include the evaporator blower assembly and a separate accumulator enclosed in an accumulator housing. The accumulator is connected to the evaporator through a fluid flow line and connector joints. The evaporator and accumulator require separate mounting parts as well as the additional labor costs of separate manufacture and assembly.
An example of a prior art refrigerant system is disclosed in the U.S. Pat. No. 2,137,260 to Boles, issued Nov. 22, 1938 and assigned to the assignee of the present application. It is common to construct the heat exchange components of such a system from a stack of plates forming successively arranged flow chambers. An example of a stacked heat exchanger is disclosed in the U.S. Pat. No. 3,240,268 to Armes, issued Mar. 15, 1966 and assigned to the assigne of the present invention.
It is the object of the present invention to overcome the difficulties of the prior art air conditioner assemblies including separate evaporator and accumulator components.
More particularly, it is an object of the present invention to decrease the thermal loss inherent in present day evaporator and accumulator components, decrease the overall space required by present day systems, and eliminate the amount of parts, materials and labor costs.